问题
选择题
_______ you ________ stay at home this evening? [ ]
A. Are; have to
B. Do; have to
C. Did; has to
D. Do; has to
答案
答案：B
搜题请搜索小程序“爱下问搜题”
_______ you ________ stay at home this evening? [ ]
A. Are; have to
B. Do; have to
C. Did; has to
D. Do; has to
答案：B
存在，则f(1)=（）。